Protecting grate



Feb. 27, 1945. c. R. DAVISON PROTECTING GRATE Filed June 17, 1942 2 Sheets-Sheet 1 IEIFIEIEU NWE 0 WWW, Z w gm Feb. 27, 1945. c. R. DAVISON PROTECTING GRATE Filed June 1'7, 1942 2 Sheets-Sheet 2 Asa ear C fiar/aaw J! Maw w firm/way Patented Feb. 27, 1945 PROTECTING GRATE Charles It. Davison, Erie, Pa., assignor to The Standard Stoker Company, Incorporated, a' corporation of Delaware Application June 17, 1942, Serial No. 448,064

17 Claims.

My invention relates to protecting grates for mechanical stokers and pertains more particularly to sectional protecting grates for the discharge conduit of that type of stoker in which the discharge conduit extends upwardly through the firebox grate and terminates in a delivery opening above the level of the fire.

Protecting grates have previously been made up of several heavy and cumbersome sections making installation and renewal thereof troublesome, time consuming and expensive. It is also frequently necessary to renew one or more of these sections in their entirety although they are only partially destroyed by the heat in the firebox. The present invention, therefore, has as one of its objects the reduction in time, trouble and expense in effecting installation and renewal of protecting grates and reduction in maintenance costs.

The sections ofprior protecting grates, because of their bulk and irregular shape result in high production cost and his, therefore, another object of the invention to reduce the cost of manufacture of protecting grates.

A further object of the invention is to provide a sectional protecting-grate of the'above type em bodying novel interlocking means whereby sections thereof may be readily and conveniently removed and replaced, particularly those sections which are most subject to deterioration by the heat of the firebox.

Still another object of the invention is to provide a sectional protectinggrate of the above type in which the sections of the greater part thereof are so constructed as to be readily interchangeable.

To the above ends, my improved protecting grate comprises a plurality of parts so constructed and designed to form a securely interlocked unit; that is readily and conveniently assembled, installed, removed and replaced; and that when assembledforms a compact and simple unit; the greater number of the parts thereof being interchangeable and so designed and formed for economical manufacture.

Other objects and advantages of the invention portion of the locomotive firebox, looking downwardly at the delivery end of the stoker and the novel protecting grate, parts of the stoker being broken away;

Fig. 3 is an isometric view of one of the interchangeable sections of the novel protecting grate; and i Fig. 4 is an isometric view of one of the respective end sections of the novel protectinggrate.

For purpose of illustration the invention has been shown as applied to aflocomotiv'efirebox, but it is apparent that the invention is applicable to any type of firebox in which the delivery portion of the stoker extends into-thecombustion chamber. v Referring to the drawings, the numeral Ill indicates a firebox having fuel supporting grates l I and a backwall or rear water leg I2 provided with a conventional fire door opening l3. Fuel is delivered to the firebox through a conduit Min which is located the fuel conveying screw l 5. The conduit l4 terminates in an upwardly curving elbow l6 which merges into the straight tubular conduit or riser conduit IT. The riser conduit l1 terminates in a mouth l8 above the level of the fire in the firebox l0.

A metal plate or firing table l9 fits about the mouth l8 of the riser conduit ll and rests at its inner edge on lugs Zllprojecting from the outer face of the riser conduit 11. Secured at the up-. per rearward end of the conduit I1 is a chambered distributor head 2! which is providedwith jet "distributor head 2| are wellknown in the art and reside in the features of construction, the comis therefore not shown or .described.

The center bearer bar 23 that supports the fuel supporting grates H is forked at its rearward end to provide an opening through which the stoker riser conduit l1 extends. Partially surrounding the riser conduit" is .the novel auxiliary or protecting grate 24 which shields the conduit I! from the direct heat of the fire in the firebox l0. As shown in the drawings, the stoker riser conduit I! extends upwardly closely adjacent the firebox backwall l2, so that the rearward portion of the conduit need not be enclosed by the protecting grate 24.

The novel protecting grate 24 includes a lower portion or base grate 25 having an upright, preferably cast metal wall 26 generally U-shaped in Fig. 1, is provided in its upper face with a groove 29 extending completely thereabout, and with a plurality of spaced vertically extending apertures ,30 opening into the groove 29. The base grate is preferably formed of a plurality of sections, shown in the drawings as being comprised of the two sections 3| and 32, though obviously it. may be formed as an integral casting.

The upper or main portion of the protecting rate 24 comprises a plurality of upright generally rectangularly shaped'preferably cast metal sections 33, as best shown in Fig. .3, and a pair of terminal sections 34, as best shown in Fig. 4. The lower ends of the rate sections '33 and 34 are received in-the U-shaped groove 29 of the base grate 25 and the upper ends of the grate sections 33 and 34 terminate slightly below the lower outer edge of the firing table l9. When assembled, the grate sections 33 and 34 extend about the stoker riser conduit I! in a substantially U-shape, the open end of the assembly being adjacent the backwall i2.

The opposite faces 35 and 38 of the grate sections 33 are parallel with respect to each other and the side edge faces 31 and 38 converge from face 35 toward face 35 on a common axis, i. e., the angle between the side edge face 31 and the face 35 being the sam as the angle between the side edge face 38 and the face .35. Thus each of the grate sections 33 is in the form of a truncated isosceles triangle in horizontal cross section having a face 35 of greater width than its opposite face 33. v

In assembling the grate sections 33, they are inserted in the straight portions of the U -shaped roove 29 of the base grate 25in abutting relation with alternately the wide face 35 of one facing outwardly and the narrow face 33 of the other facing outwardly. Around the arcuate portion of the groove 29, the great sections 33 are inserted with the wide face 35 of each facing outwardly. The radius of curvature of the are formed by the grate'sections 33 when their wide faces 35 all face outwardly is of course determined by the angle of convergence between the side edge faces 31 and 38 of the grate sections 33. Thus any desired radius of curvature can be provided by suitably increasing or decreasing the angle of convergence.

It is apparent, of course, that the grate sections forming the straight portions of the U- shaped configuration, could be formed with their side edge faces at right angle with respect to the faces 35 and 36,. however this would necessitate one style of grate section for the straight portion of the U-shaped configuration and another style of grate section for the arcuate portion of the U-shaped configuration. In thepresent construction and arrangement, the grate sections forming the straight portions of the U-' shaped configuration are identical with the grate sections forming the arcuate portion of the U- shaped configuratiomyand are therefore interchangeable. The advantages of such a construction and arrangement can readily be appreciated.

Each of the grate sections 33 is provided in its side edge faces 31 and 38 with a vertical groove 39 and a plurality of horizontal grooves 40. When the grate sections 33 are assembled, the vertical grooves 39 in the abutting side edge faces of each pair of adjacent grate sections complement each other to form a plurality of vertical passages communicating with respective openings 30 in the base grate 25. Likewise, the horizontal grooves 40 in the abutting side edge faces of each pair of adjacent grate sections complement each other to form a plurality of horizontal passages through the grate assembly.

The passages formed by the longitudinal grooves 39 and the passages formed by the horizontal grooves 40, serve to permit a flow of cooling air therethrough from the ash pit, thereby cooling the protecting grate 24 and prolonging its life. The firebox draft draws the air through the described passages into combustion chamber so that besides acting as a cooling medium for the protecting grate, the air assists in the combustion of the fuel. The base grate 25 is pro- .vided with a plurality of apertures 4| having-a A function similar tothe passages above described.

The terminal grate sections 34 have only one angularly disposed side edge face 42, in which there is a vertical groove 43 and horizontal grooves 44 identical with the grooves in the grate sections '33. Filler plates 45 are secured to the terminal grate sections 34 by means of bolts 43 to close the gap between the protecting grate assembly. and the backwall l2. The terminal grate sections are provided with holes 41, as shown in Fig. 4, for receiving the bolts 46.

The upper end of each of the grate sections 33 is-provided with a laterally extending groove 43 and each of the terminal grate sections 34 is provided with a laterally extending groove 49. When the grate sections 33 and 34 are assembled, the grooves 43 and 43 form a continuous U-shaped groove in which is received a U-shaped rod 53. Theends of the U-shaped rod extend through .a plate 5| disposed transversely across the open end of the U-shaped grate assembly and nuts 52 threaded on the free ends of the rod 53 are drawn up tightly against the plate 5|, thereby locking the grate sections-33 and 34 in position.

I claim: I

l. A protecting grate for a heat exposed stoker fuel discharge conduit, said protecting grate being. arcuate in horizontal cross section and comprising a plurality of upright laterally abutting sections, each of said sections having a groove in its upper end extending from one abutting face 'to the opposite abutting face thereof, said grooves being in end to end communication to form a continuous groove in the upper end of said protecting grate, and means engaging said continuous groove arranged to securesaid laterally abutting plurality of sections together.

2. A protecting grate for a heat exposed stoke:- fuel discharge conduit, said protecting grate being arcuate in horizontal cros section and comprising a plurality of elongated upright laterally abutting sections, said sections each having a pair of opposed parallel faces forming the inner and outer sides of said protecting grate and a pair of opposed side faces converging on a common axis forming the meeting faces of the abutting sections of said protecting grate, the meeting faces a of abutting grate sections being provided between their respectiveupper and lower ends with a phirality of spaced complementary groves opening and means engaging said upright grate sections through said parallel faces and forming passages through said protecting grate.

3. A protecting grate for a heat exposed stoker fuel discharge conduit, said protecting grate being arcuate in horizontal cross section and comprising a plurality of upright laterally abutting sections, the meeting faces of abutting grate sections being provided with complementary transverse grooves forming passages through said protecting grate, each of said grate sections also having a groove in its upper end extending from one abutting face to the opposite abutting face thereof, said last named grooves being in end to end communication to form a continuous groove in the upper end of said protecting grate, and means engaging said continuous groove arranged to secure said plurality of sections together.

4. A protecting grate for a heat exposed stoker fuel discharge conduit, said protecting grate being U-shaped in horizontal cross section and including straight and arcuate portions, said protecting grate comprising a plurality of upright laterally abutting grate sections, each of said sections being in the form of an isosceles trapezoid in horizontal cross section providing each of said sections with a wide face and a narrow face, the straight portion of said protecting grate comprising a plurality of said grate sections with alternate wide and narrow faces forming the respective sides of the protecting grate and the curved portion of said protecting grate comprising a plurality of said grate sections with their wide faces forming one side of the protecting grate and their narrow faces forming the opposite side thereof, said sections being of similar configuration and being interchangeable.

5. A protecting grate for a heat exposed stoker fuel discharge conduit, said protecting grate being U-shaped in horizontal cross section and including straight and arcuate portions, said protecting grate comprising a plurality of upright laterally abutting grate sections, each of said sections being in the form of an isosceles trapezoid in horizontal cross section providing each of said sections with a wide face and a narrow face, the straight portion of said protecting grate comprising a plurality of said grate sections with alternate wide and narrow faces forming the respective sides of the protecting grate and the curved portion of said protecting grate comprising a plurality of said grate sections with their wide faces forming one side of the protecting grate and their narrow faces forming the opposite side thereof, said sections being of similar configuration and being interchangeable, each of said grate sections having a groove in its upper end extending from one abutting face to the opposite abutting face thereof, said grooves being in end to end communication to form a continuous groove in the upper end of said protecting grate, and means engaging said continuous groove arranged to secure said plurality of sections together.

6. A protecting grate for a heat exposed stoker fuel discharge conduit, including a base grate portion arcuate in horizontal cross section, said base grate portion being in the form of an upstanding wall having a flange extending inwardlyv from the upper edge thereof, said flange having a groove formed in its upper end following the contour of the said base portion, an upper grate portion following the contour of said base grate portion, said upper grate portion comprising a plurality of upright sections fitting at their lower ends in the groove of said base grate portion,

for securing them in position.

' "I. A protecting grate for aheat exposed stoker fuel discharge conduit, including a base'grate portion arcuate in horizontal cross section, said base grate portion being in the form of an upstanding wall having a groove formed in its upper end following the contour of the said base por-' tion and aplurality of apertures between the upper and lower ends of said upstanding wall opening interiorly and exteriorlyof said base grate, an upper grate portion following the contour of said base grate portion, said upper grate portioncomprising a plurality of upright abutting sections fitting at their lower ends in the groove of said b grate portion, the meeting faces of abutting gratesections being provided with complementary transverse grooves forming passages through said upper grate portion, and

means engaging said upright grate sections for securing them in position.

8. A protecting grate for a heat exposed stoker fuel discharge conduit, including a base grate portion arcuate in horizontal cross section, said base grate portion having a groove formed in its upper end following the contour of the said base portion, an upper grate portion following the contour of said base grate portion, said upper grate portion comprising a plurality of upright sections fitting at their lower ends in the groove of said base grate portion, each of said sections having a groove in its upper end, said grooves being in end to end relation to form a continuous groove in the upper end of said protecting grate, and means'engaging said continuous groove for securing said upright grate sections in position.

'9. A protecting grate for a heat exposedstoker fuel discharge conduit; including abasegrate portion arcuate in horizontal cross section, said base grate portion having a groove formed in its upper end following the contour of the said base portion; an upper grate portion following the contour of said base grate portion, said upper grate portion comprising a, plurality of upright abutting sections fitting at their lower ends in the groove of said base grate portion, the meeting faces of abutting grate sections being provided with complementary transverse grooves forming passages through said upper grate portion, each of said sections having a groove in its upper end, said last named grooves being in end to end relation t form a continuous groove in the upper end of said protecting grate, and means engaging said continuous groove for securing said upright grate sections in position.

10. A protecting grate for a heat exposed stoker fuel discharge conduit, including a base grate portion arcuate in horizontal cross section, said base grate portion having a groove formed in its upper end following the contour of the said base portion and a plurality of apertures opening downwardly to the inner side of the said base grate portion and opening upwardly to said groove, an upper grate portion following the contour of said base grate portion, said upper grate portion comprising a plurality of upright abutting grate sections fitting at their lower ends in the groove of said base grate portion, the meeting faces of abutting grate sections being provided with complementary vertical grooves forming passages extending through said upper grate portion and communicating with the apertures in said base grate portion, and means engaging said upright grate sections for securing them in position.

11. A protecting grate fora heatexposed stoker fuel discharge conduit, including a base grate portion arcuate in horizontal cross section, said base grate portion having a groove formed in its upper end following the contour of the said base portion and a plurality of apertures opening downwardly to the inner side of the said base grate portion and opening upwardly to said groove, an upper grate portion following the contour of said base grate portion, said upper grate portion comprising a plurality of upright abutting grate sections fitting at their lower ends in the .grooveof said base grate portion, the meeting .faces of abutting grate sections being provided with complementary transverse grooves forming passages through said upper grate portion and also provided with complementary vertical grooves forming passages extending through said upper grate portion and communicating with the apertures in said base grate portion, and means engaging said upright grate sections for securing them in position.

12. As an article of manufacture, a section of a protecting grate for a heat exposedstoker fuel discharge conduit, said grate section comprising anelongated body having a pair of opposed parallel plane faces, a. pair of opposed side faces converging on a common axis, and a pair of op osed and faces, one of said end faces having a groove between and parallel to said parallel faces and opening through said side faces.

13. As an article of manufacture, a section of a protecting grate for a heat exposed stoker fuel discharge conduit, said grate section comprising an elongated body having a pair of opposed parallel plane faces, a pair of opposed side facesconverging on a common axis, and a pair of opposed parallel end faces, said side faces having a plurality of spaced grooves between said end faces and opening through said parallel faces.

14. As an article of manufacture, a section of a protecting grate for a. heat exposed stoker fuel discharge conduit, said grate section comprisim an elongated body having a pair of opposed parallel faces, a pair of opposed side faces converging end faces, and opening through said parallel faces, and one of said end faces having a. groove between said parallel faces and opening through said side faces.

15. As an article of manufacture, a section of a protecting grate for a heat exposed stoker fuel discharge conduit, said grate section comprising an elongated body having a pair of opposed parallel plane faces, a pair of opposed side faces converging on a common axis, and a pair of opposed end faces, said side faces having grooves between said parallel faces opening through said end faces and a plurality of spaced grooves between said end facesopening through said parallel faces and intersecting said first named grooves.

16. As an article of manufacture, a base section of a protecting grate'for a heat exposed stoker fuel discharge conduit, said base grate section being in the form of an upstanding wall curvate in horizontal cross section and having a flange extending inwardly from the upper edge of said upstanding curvate wall, said flange having a groove formed in its top face following the contour of the upper end of said base grate section.

17.. As an article of manufacture, a base section of a protecting grate for a heat exposed stoker 'fuel discharge conduit, said base grate section being in the form of. an upstanding wall curvate in horizontal cross section and having a flange extending inwardly from the upper edge of said upstanding curvate wall, said flange having a groove formed inits top face following the contour of the upper end of said base grate section,

and a plurality of apertures opening downwardly to the inner side of said base grate section and opening upwardly to said groove.

, CHARLES R. DAVISON. 

